The present invention provides an improvement in the provision of structural connecting element of a conventional cross sectional configuration that are available in lumber supply outlets of the kind that are generally used to frame door or window openings. The longitudinal forming elements of the invention are those of thermoplastic composition variety which lend themselves to thermoforming. The thermoformed shapes produced according to the invention, while not limited thereto, has particularly advantageous application in the securing of a preformed stair module in in a swimming pool wall opening and to the swimming pool wall. The thermoformed framing or face plate of the invention functions also to secure a swimming pool vinyl liner on the pool wall at the edges of the stairwell opening. Such vinyl liners are conventional in pools of this kind and are use to cover the pool wall and bottom and extend to peripheral edge of the stair module. The framing/connecting member which is thermoformed according to the invention is employed in combination with a gasket arrangement to secure against the leakage of water at the juncture of the stair module and the pool wall and comprises the exposed face plate bordering the stairwell opening.
Heretofore, stair mount connecting/framing or facing elements have generally been formed of separate pieces that are butted or mitered to the desired angle to accommodate the shape of the opening at which the face plate or frame is to be applied. Such prior art arrangements have been unsatisfactory aesthetically as well as functionally because of the difficulty of providing a smooth joint at the corners of the components forming the face plate or frame. Additionally, a proper fitting and securing of conventional multiple parts that are mitered or butted to provide the frame or face plate have been time consuming and difficult. Because of the relatively sharp corners resulting from an assembly of multiple piece frames, such have been the cause of snagging and tearing of vinyl swimming pool liners.
Accordingly, a need exists for the provision of an improved joinder arrangement in lieu of a structure formed from abutting a plurality of pieces to form the face plate or framing element. More particularly, a need exist for a means to provide a swimming pool wall opening with a unitary (continuous) framing member which provides a face plate and frames and covers the peripheral edge of a preformed stair module that has been fitted into the wall opening of an inground swimming pool.